Hi,
One of my wind surf student's sail after usage of 5 years it disbanded. I replaced all the windows. I used 6 m2 opaque color mono film, 0.5 m2 white dacron. I spent 30 hours in my workshop to repair the sail. It cost me 40 US dollars. New sails are quite expensive that's why I repair my teen student's
sails. So they can continue windsurfing.
Original sail is: North Sails 4.7 Curve.